Accelerating particles to high velocities



Dec. 12, 1967 C. A. BOYD ETAL.

ACCELERATING PARTICLES TO HIGH VELOCITIES Filed June 29, 1965INVENTOILS` CHA/M55 A. 907D Y PH/L/P G. LUCKHARDT United States Patent O3,357,306 ACCELERATING PARTICLES T HIGH VELUCITIES Charles A. Boyd andPhilip G. Luckhardt, West Chester,

Pa., assignors to Aeroprojects Incorporated, West Chester, Pa., acorporation of Pennsylvania Filed June 29, 1965, Ser. No. 468,006Claims. (Cl. 89-8) This invention relates to apparatus invented foraccelerating particles or projectiles so that they may attain highvelocities.

The present invention permits relatively large projectiles of known massto be directed toward a target at high velocities. In this manner,laboratory studies for impact effects on various structures andmaterials are facilitated. Accordingly, meteor impact problems, missilenose cone design, inter alia, maybe studied under a condition simulatingouter space.

One of the major obstacles to such studies in the laboratory is toprovide a means for creating sufficiently high velocities for relativelylarge projectiles. The present invention overcomes this obstacle bysequentially accelerating a moving projectile. The sequentialacceleration is preferably accomplished by sequentially detonatingexplosive shaped charges along the path of the projectile so that theexplosive force of each shape charged further accelerates'theprojectile.

It is an object of the present invention to provide a novel apparatusforaccelerating projectiles.

It is another object of the present invention to provide a novel methodof accelerating projectiles.

It is another object of the present invention to provide a novel methodand apparatus for accelerating projectiles at very high velocities tofacilitate laboratory studies of impact problems and the like.

It is another object of the present invention to provide a method andapparatus for simulating outer space Conditions for impact studies ofmeteorites and the like.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there are shown in thedrawings forms which are presently preferred; it being understood,however, that this invention is not limited to the precise arrangementsand instrumentalities shown.

FIGURE l is a diagrammatic illustration of the present invention shownin section.

FIGURE 2 is a sectional view taken along the line 2 2 in FIGURE 1.

FIGURE 3 is a view similar to FIGURE 2 but illustrating anotherembodiment.

Referring to the drawing in detail, wherein like numerals indicate likeelements, there is shown in FIGURE 1 an apparatus designated generallyas 10.

The apparatus includes a housing 12 which may be cylindrical as shownmore clearly in FIGURE 2. The housing 12 is provided with end walls 14and 16. The

interior of the housing 12 is provided with partitions 18,.

22 and 26. End wall 14 and partition 18 cooperate with the housing 12 todefine a chamber 20.

Partitions 18 and 22 cooperate with the housing 12 to define a chamber24. Partitions 22 and 26 cooperate with the housing 12 to define achamber 28. Partition 26 and end wall 16 cooperate with the housing 12to form a chamber 30. The chambers 20, 24, 28 and 30 are seriallydisposed. If desired, a thin walled tube 32 made from a material such asaluminum may be coaxially disposed within the housing 12 and extendingbetween an inlet in the wall 14 to an outlet in the wall 16. Anysuitable means such as nuts and bolts may be used to retain the tube 32in a predetermined disposition.

The barrel 34 of a gun, not shown, extends through the 3,357,306Patented Dec. l2, 1967 inlet in end wall 14 in line with the tube 32.The gun is preferably a pneumatic gun for firing projectile 36 throughthe tube 32 toward the target 38. Target 38 may be supported externallyof the housing 12 in any convenient manner or may be completelydisconnected from the accelerator. For some laboratory studies, thetarget 38 may be supported by a tubular extension 39 having a chamber 41therein. Chamber 41 may be evacuated by means of conduit 43 as will bemade clear hereinafter.

Within chamber 20, there is supported an annular shaped charge 40 havinga detonator 42. A means is provided for sensing the presence of theprojectile 36. This may be simply accomplished by providing suitableapertures in opposite sides of the tube 32, and utilizing an opticalsensing means such as photoelectrc cells 44 and 46. As the projectile 36interrupts the beam between the cells 44 and 46, current will besupplied to the detonators 42 to detonate the same. The cells 44 and 46are spaced from the shaped charge 44 by a distance so that the shapedcharge 40 will be detonated at a time interval whereby its explosiveforce will accelerate propulsion of the projectile 36.

The shaped charge 40 may be supported in any convenient manner such asby brackets 48. Within chamber 24, there is provided comparablephotoelectrc cells, shaped charge and detonator provided with primed`numerals. The photoelectrc cells 44 and 46 are spaced slightly furtherfrom the shaped charge 40. The spacing takes into consideration that theprojectile will be moving faster when passing through chamber 24. Inchamber 28, there are provided corresponding elements with double primednumerals. The cells 44 and 46" are spaced further from the shapedcharge. 40 as compared with the corresponding elements in chamber 24.

The various chambers within the housing 12 as Well as chamber 41 arepreferably evacuated for meteoroid simulation studies, but need not beevacuated for other studies. This may be accomplished by a manifold 50.Chamber 20 and manifold 50 are interconnected by conduit 52. Chamber 24and manifold 50 are interconnected by conduit 54. Chamber 28 andmanifold 50 are interconnected by conduit 56. Chamber 30 and manifold 50are interconnected by conduit not shown. Chamber 41 and manifold 50 areinterconnected by conduit 43. A vacuum pump 58 may be provided with itsinlet side communicating with the manifold 50.

The operation of the apparatus 10 is as follows:

A projectile 36 of large mass is fired through barrel 34 into the tube32. For meteorite impact studies, a large mass would be one gram. As theprojectile 36 interrupts the light beam between cells 44 and 46', thedetonator 42 is detonated thereby exploding the shaped charge 40. Theexplosive force of shaped charge 40 bursts the portion of tube 32immediately adjacent thereto and accelerates the speed of the projectile36. As the projectile 36 enters the chambers 24, it will interrupt thelight beam between cells 44 and 46'. As a result thereof, the shapedcharge 40 will be detonated bydetonator 42. This explosive force willlikewise accelerate the speed of the projectile 36. The above sequencewill be repeated throughout the length of the housing 12, as desired, sothat the explosive force of each shaped charge will sequentiallyincrease the speed of the projectile so that speeds of at least 10,000meters per second may be attained when the projectile contacts thetarget 38. If desired, the pressure on opposite sides of the target maybe equal or substantially equal by extending the length of the chamber41.

Doors not shown are provided in the housing 12 so that access may be hadto each of the chambers therein to facilitate replacement of the shapedcharge and detonators. After each firing the tube 32 will be replaced.It will be appreciated that the drawing is only schematic in thatreinforced ribbing, and a rigid support to counteract the explosiveforce from the shaped charges, etc. will be provided. For certaintesting operations, the thin walled aluminum guide tube 32 may beeliminated. For purposes of illsutration, the projectile is illustratedas having a spherical shape. It will be appreciated that other contoursmay be provided for the projectile 36. It will be appreciated by thoseskilled in the ar-t that the super high velocity gas jet formed by theexplosion of the shaped charges gives the projectile 36 a velocity boostby momentum transfer.

In FIGURE 3 there is illustrated an alternate arrangement wherein acylindrical charge 60 may be substituted for the shaped chargesidentified above. When using cylindrical charges, the projectile 36'should have a conical tail section providing a reaction surface 6,2. Theforce or momentum of the explosion products imploding inwardly in aradial direction from charge 60 immediately destroys the juxtaposedportion of tube 32 and acts on surface 62 .to provide a force componentthereon to propel projectile 36' forwardly in the same manner asdescribed above. In this way it will be seen that, theoretically atleast, the terminal velocity of the projectile can exceed the particlervelocity of the imploding gas. It will be noted that the .charges inFIGURES l-3 are annular.

The .present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing speciiication as indicating the scope of theinvention.

We claim:

1. Apparatus for accelerating projectiles to high velocities comprisinga housing, means for evacuating said housing, a plurality of alignedannular explosive charges vin said housing, said housing having an inletand an outlet aligned with said charges, sensing means for sequentiallyfiring each charge whereby each charge will accelerate the speed of aprojectile passing through said housing and partitions dividing saidhousing into separate chambers, means for supporting the charges in saidchambers, and each charge having its own sensing means coupled thereto.

2. Apparatus in accordance with claim 1 including a thin walled guidetube extending through said partitions between said inlet and saidoutlet and through which the projectile will be propelled, with thercharges being annularly disposed around said tube..

3. Apparatus in accordance with claim 1 wherein said sensing means is anoptical sensing means.

4. Apparatus in accordance with claim 1 including a target supported bythe housing, said housing having a chamber between the target land thecharge closest to the target, said last mentioned chamber beingevacuated by said evacuating means.

5. Apparatus in accordance with claim 1 wherein said sensing meansincludes an optical sensing means associated with each of thecharges-which are shaped charges, the distance -between the shapedcharges and their respective optical sensing means being progressivelyfarther from each other in a direction extending from the inlet towardthe outlet, whereby the distance ,betweenithe sensing means and .shapedcharge adjacent the inlet is less than the corresponding distancebetween the sensing means and shaped charge adjacent the outlet.

References Cited UNITED STATES PATENTS 3,031,933 5/ 1962 Kern et al.89-8 3,054,329 9/ 1962 Willig 89.-8 X 3,065,695 11/ 1962 Jarrett 102-243,132,562 5/ 1964 Frevel `89-8 X v3,215,074 ll/ 1965 Robinson et al.102-,-24

SAMUEL W. ENGLE, Prima-:jy Examiner.

1. APPARATUS FOR ACCELERATING PROJECTILES TO HIGH VELOCITIES COMPRISINGA HOUSING, MEANS FOR EVACUATING SAID HOUSING, A PLURALITY OF ALIGNEDANNULAR EXPLOSIVE CHARGES IN SAID HOUSING, SAID HOUSING HAVING AN INLETAND AN OUTLET ALIGNED WITH SAID CHARGES, SENSING MEANS FOR SEQUENTIALLYFIRING EACH CHARGE WHEREBY EACH CHARGE WILL ACCELERATE